Motor vehicle door assemblies typically comprise an outer door panel, which defines the external contour of the door assembly, mounted along its peripheral edges to an inner door panel, which defines the internal contour of the door assembly, and upon which decorative interior panels are mounted forming portions of the motor vehicle interior. In situations where weight savings are critical (auto manufacturers prefer steel, weight is not as critical as it is for trucks) the inner and outer door panels typically comprise a moderate strength, lightweight metallic material, such as aluminum. A relatively large, hollow interior area is formed between the outer and inner panels, including a peripheral portion which mates with the motor vehicle door framework to seal the vehicle interior from the exterior and a central portion wherein various accessory mechanisms are mounted, such as window raising and lowering mechanisms, door latching and locking mechanisms, and the like. The inner panel is conventionally provided with openings to provide access to the interior area for assembly, adjustment, repair, or replacement of the various mechanisms mounted in the interior area. The access openings, however, regardless of their placement and dimension, provide only limited access to mechanisms mounted in the interior area between the inner and outer door panels, and assembly, adjustment, repair and replacement of the various mechanisms is inconvenient and time consuming.
All motor vehicle door assemblies must meet vehicle safety standards prescribed by the federal government. Conventional door assemblies having inner and outer panels defining a generally hollow interior area are not generally reinforced by higher strength materials (when weight is not a factor), so that the structural integrity and rigidity of the inner and outer door panels alone provides strength and rigidity to the door assembly. Providing door assemblies which exceed the prescribed vehicle safety standards is desirable to enhance vehicle and passenger safety. Moreover, vibration of the panels comprising conventional door assemblies and the accessory mechanisms mounted in the interior area often results in damage to the door panels and/or the mechanisms mounted therein.
Assembly of motor vehicle door panels and mounting of the mechanisms therein has typically taken place in a step-wise fashion which is time and labor intensive, and therefore costly. Recent efforts in the automotive industry have been directed to reducing costs, and particularly labor costs for assembly, maintenance and repair of motor vehicles. The use of modular assemblies which significantly reduce labor costs incurred in motor vehicle assembly, and significantly reduce the time required for motor vehicle assembly, has recently been recognized as an important factor in reducing motor vehicle assembly costs and improving productivity. An article in the July 27, 1987 issue of Automotive News, at page E26, describes the efforts of a major manufacturer to engineer and manufacture modular systems and subassemblies for the motor vehicle industry.
It is an object of the present invention to provide a door assembly using aluminum for structure and steel for reinforcement, realizing thereby a significant weight savings over the use of a complete steel door.
It is another objective of the present invention to provide a motor vehicle door assembly having safety features which increase the structural strength and rigidity of the door assembly and provide enhanced vehicle safety while reducing the weight of the complete door assembly.
It is another objective of the present invention to provide an improved motor vehicle door assembly which facilitates rapid motor vehicle assembly and which is especially suitable for use with sub-assembled accessory mechanisms.
It is another objective of the present invention to provide an improved motor vehicle door assembly which facilitates convenient access to various accessory mechanisms mounted on the door assembly for assembly, adjustment, repair, or replacement purposes.
It is still another objective of the present invention to provide a rigid reinforcement panel for installation on a door panel to increase the structural strength and rigidity of the door assembly, thereby enhancing vehicle safety.
It is a further objective of the present invention to provide an improved motor vehicle door assembly including a rigid reinforcement panel which reduces motor vehicle assembly costs, particularly labor costs, and which simultaneously reduces motor vehicle production times.